The present invention relates to a nitride semiconductor device where a nitride semiconductor is used as an active layer and a manufacturing method for the same, and in particular, to a nitride semiconductor device having, a control electrode that makes Schottky contact with the semiconductor device, such as a high electron mobility transistor (HEMT) and a field effect transistor (FET), and a manufacturing method thereof.
FIG. 6 is a cross sectional diagram of a semiconductor device made of a conventional III-V group nitride semiconductor. The semiconductor device shown in FIG. 6 has a so-called HEMT structure where a buffer layer 102 made of gallium nitride (GaN), a channel layer 103 made of gallium nitride, a charge supply layer 104 made of n type aluminum gallium nitride (AlGaN) and a Schottky layer 105 made of undoped aluminum gallium nitride are sequentially deposited on a substrate 101 made of a sapphire substrate, where a two-dimensional electron gas layer made of a potential well and having an extremely high electron mobility is formed in the vicinity of the interface where the channel layer 103 and the charge supply layer 104 form a hetero junction. In the semiconductor device having such a structure, a voltage that is applied to a gate electrode 106 (control electrode) that makes Schottky contact with the Schottky layer 105 is controlled, and thereby, carriers (two-dimensional electron gas) that flow between a source electrode 107a and a drain electrode 107b are controlled.
A variety of structures as disclosed in, for example, Japanese Unexamined Patent Publication No. 335637/1998, in addition to the above described structure.